I have a 91 Seaswirl Sierra Classic, it's an i/o, and would need to know whats the best way to get the largest, peakiest wake out of an i/o using ballast. I can have about 800 lbs max., and price does not matter. I would only like to use fat sacs, no permanent weights (i.e lead, sand). Also, I would not want to go any faster than 24 mph to wakeboard. thanks in advance!

With the I/O I had for 3 years (19ft 4.3L EFI) I weighted it with: 1 Fat Sac (~550lbs) in the rear 1 Tube Sac in the bow (~375lbs) about 350lbs of sand in the bow and front of ski locker. (a tube sac in the ski locker would work nicely too) Weight in the bow is very important!

Wake was nice and firm at 21+mph 75ft or less

When it was calm out we could use the trim and get a huge rampy wake too (almost doubled in size!)

A good prop is also must to get the boat moving and maintain speed. I used a 21 pitch 5 blade stainless

What is the setup of your boat in the rear? Bench seat with full sunpad over engine area? Or is there an engine box with seats next to it?

My boat was setup with the full sunpad/bench seat. If you need to have only water ballast and it has to be out of the way, a Fly High Tube sac (375lbs)fit under my bench seat perfectly. The same Sac also fits nicely in the ski locker under the floor. So there's 750lbs out of the way.

I don't know how much room you have up in the bow under the seats, maybe you could fill a small sac partially under each seat? This is where I used gallon jugs filled with sand. I left them there permanently because even when not wakeboarding, the extra weight in the front helped balance the boat out and it drove much better. Boat was able to plane much quicker and also drove thru chop a lot smoother. Maybe you can make a compromise with you Dad? Do whatever you need to do to get some weight in the bow.

I think the setup would work very nicely for you: 375lbs in rear 375lbs in ski locker 250lbs in bow ------ 1000lbs total

Best of luck

P.S. I think your Dad would have hated the setup on my boat, Full sac on Floor in rear, Tube sac in bow/walkthru, Sand under bow seats and in ski locker. Extended pylon right in center of boat with support arms going toal! Very Functional! Not very Ergonomic! The new boat will be soo nice! (picking it up on the 11th)